/*******************************************************************************
 * Copyright (c) 2011 Google, Inc.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Google, Inc. - initial API and implementation
 *******************************************************************************/
package movieGandalf.GUI;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Cursor;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.FontData;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Display;

/**
 * Utility class for managing OS resources associated with SWT controls such as colors, fonts, images, etc.
 * <p>
 * !!! IMPORTANT !!! Application code must explicitly invoke the <code>dispose()</code> method to release the
 * operating system resources managed by cached objects when those objects and OS resources are no longer
 * needed (e.g. on application shutdown)
 * <p>
 * This class may be freely distributed as part of any application or plugin.
 * <p>
 * @author scheglov_ke
 * @author Dan Rubel
 */
public class SWTResourceManager {
        ////////////////////////////////////////////////////////////////////////////
        //
        // Color
        //
        ////////////////////////////////////////////////////////////////////////////
        private static Map<RGB, Color> m_colorMap = new HashMap<RGB, Color>();
        /**
         * Returns the system {@link Color} matching the specific ID.
         * 
         * @param systemColorID
         *            the ID value for the color
         * @return the system {@link Color} matching the specific ID
         */
        public static Color getColor(int systemColorID) {
                Display display = Display.getCurrent();
                return display.getSystemColor(systemColorID);
        }
        /**
         * Returns a {@link Color} given its red, green and blue component values.
         * 
         * @param r
         *            the red component of the color
         * @param g
         *            the green component of the color
         * @param b
         *            the blue component of the color
         * @return the {@link Color} matching the given red, green and blue component values
         */
        public static Color getColor(int r, int g, int b) {
                return getColor(new RGB(r, g, b));
        }
        /**
         * Returns a {@link Color} given its RGB value.
         * 
         * @param rgb
         *            the {@link RGB} value of the color
         * @return the {@link Color} matching the RGB value
         */
        public static Color getColor(RGB rgb) {
                Color color = m_colorMap.get(rgb);
                if (color == null) {
                        Display display = Display.getCurrent();
                        color = new Color(display, rgb);
                        m_colorMap.put(rgb, color);
                }
                return color;
        }
        /**
         * Dispose of all the cached {@link Color}'s.
         */
        public static void disposeColors() {
                for (Color color : m_colorMap.values()) {
                        color.dispose();
                }
                m_colorMap.clear();
        }
        ////////////////////////////////////////////////////////////////////////////
        //
        // Image
        //
        ////////////////////////////////////////////////////////////////////////////
        /**
         * Maps image paths to images.
         */
        private static Map<String, Image> m_imageMap = new HashMap<String, Image>();
        /**
         * Returns an {@link Image} encoded by the specified {@link InputStream}.
         * 
         * @param stream
         *            the {@link InputStream} encoding the image data
         * @return the {@link Image} encoded by the specified input stream
         */
        protected static Image getImage(InputStream stream) throws IOException {
                try {
                        Display display = Display.getCurrent();
                        ImageData data = new ImageData(stream);
                        if (data.transparentPixel > 0) {
                                return new Image(display, data, data.getTransparencyMask());
                        }
                        return new Image(display, data);
                } finally {
                        stream.close();
                }
        }
        /**
         * Returns an {@link Image} stored in the file at the specified path.
         * 
         * @param path
         *            the path to the image file
         * @return the {@link Image} stored in the file at the specified path
         */
        public static Image getImage(String path) {
                Image image = m_imageMap.get(path);
                if (image == null) {
                        try {
                                image = getImage(new FileInputStream(path));
                                m_imageMap.put(path, image);
                        } catch (Exception e) {
                                image = getMissingImage();
                                m_imageMap.put(path, image);
                        }
                }
                return image;
        }
        /**
         * Returns an {@link Image} stored in the file at the specified path relative to the specified class.
         * 
         * @param clazz
         *            the {@link Class} relative to which to find the image
         * @param path
         *            the path to the image file, if starts with <code>'/'</code>
         * @return the {@link Image} stored in the file at the specified path
         */
        public static Image getImage(Class<?> clazz, String path) {
                String key = clazz.getName() + '|' + path;
                Image image = m_imageMap.get(key);
                if (image == null) {
                        try {
                                image = getImage(clazz.getResourceAsStream(path));
                                m_imageMap.put(key, image);
                        } catch (Exception e) {
                                image = getMissingImage();
                                m_imageMap.put(key, image);
                        }
                }
                return image;
        }
        private static final int MISSING_IMAGE_SIZE = 10;
        /**
         * @return the small {@link Image} that can be used as placeholder for missing image.
         */
        private static Image getMissingImage() {
                Image image = new Image(Display.getCurrent(), MISSING_IMAGE_SIZE, MISSING_IMAGE_SIZE);
                //
                GC gc = new GC(image);
                gc.setBackground(getColor(SWT.COLOR_RED));
                gc.fillRectangle(0, 0, MISSING_IMAGE_SIZE, MISSING_IMAGE_SIZE);
                gc.dispose();
                //
                return image;
        }
        /**
         * Style constant for placing decorator image in top left corner of base image.
         */
        public static final int TOP_LEFT = 1;
        /**
         * Style constant for placing decorator image in top right corner of base image.
         */
        public static final int TOP_RIGHT = 2;
        /**
         * Style constant for placing decorator image in bottom left corner of base image.
         */
        public static final int BOTTOM_LEFT = 3;
        /**
         * Style constant for placing decorator image in bottom right corner of base image.
         */
        public static final int BOTTOM_RIGHT = 4;
        /**
         * Internal value.
         */
        protected static final int LAST_CORNER_KEY = 5;
        /**
         * Maps images to decorated images.
         */
        @SuppressWarnings("unchecked")
        private static Map<Image, Map<Image, Image>>[] m_decoratedImageMap = new Map[LAST_CORNER_KEY];
        /**
         * Returns an {@link Image} composed of a base image decorated by another image.
         * 
         * @param baseImage
         *            the base {@link Image} that should be decorated
         * @param decorator
         *            the {@link Image} to decorate the base image
         * @return {@link Image} The resulting decorated image
         */
        public static Image decorateImage(Image baseImage, Image decorator) {
                return decorateImage(baseImage, decorator, BOTTOM_RIGHT);
        }
        /**
         * Returns an {@link Image} composed of a base image decorated by another image.
         * 
         * @param baseImage
         *            the base {@link Image} that should be decorated
         * @param decorator
         *            the {@link Image} to decorate the base image
         * @param corner
         *            the corner to place decorator image
         * @return the resulting decorated {@link Image}
         */
        public static Image decorateImage(final Image baseImage, final Image decorator, final int corner) {
                if (corner <= 0 || corner >= LAST_CORNER_KEY) {
                        throw new IllegalArgumentException("Wrong decorate corner");
                }
                Map<Image, Map<Image, Image>> cornerDecoratedImageMap = m_decoratedImageMap[corner];
                if (cornerDecoratedImageMap == null) {
                        cornerDecoratedImageMap = new HashMap<Image, Map<Image, Image>>();
                        m_decoratedImageMap[corner] = cornerDecoratedImageMap;
                }
                Map<Image, Image> decoratedMap = cornerDecoratedImageMap.get(baseImage);
                if (decoratedMap == null) {
                        decoratedMap = new HashMap<Image, Image>();
                        cornerDecoratedImageMap.put(baseImage, decoratedMap);
                }
                //
                Image result = decoratedMap.get(decorator);
                if (result == null) {
                        Rectangle bib = baseImage.getBounds();
                        Rectangle dib = decorator.getBounds();
                        //
                        result = new Image(Display.getCurrent(), bib.width, bib.height);
                        //
                        GC gc = new GC(result);
                        gc.drawImage(baseImage, 0, 0);
                        if (corner == TOP_LEFT) {
                                gc.drawImage(decorator, 0, 0);
                        } else if (corner == TOP_RIGHT) {
                                gc.drawImage(decorator, bib.width - dib.width, 0);
                        } else if (corner == BOTTOM_LEFT) {
                                gc.drawImage(decorator, 0, bib.height - dib.height);
                        } else if (corner == BOTTOM_RIGHT) {
                                gc.drawImage(decorator, bib.width - dib.width, bib.height - dib.height);
                        }
                        gc.dispose();
                        //
                        decoratedMap.put(decorator, result);
                }
                return result;
        }
        /**
         * Dispose all of the cached {@link Image}'s.
         */
        public static void disposeImages() {
                // dispose loaded images
                {
                        for (Image image : m_imageMap.values()) {
                                image.dispose();
                        }
                        m_imageMap.clear();
                }
                // dispose decorated images
                for (int i = 0; i < m_decoratedImageMap.length; i++) {
                        Map<Image, Map<Image, Image>> cornerDecoratedImageMap = m_decoratedImageMap[i];
                        if (cornerDecoratedImageMap != null) {
                                for (Map<Image, Image> decoratedMap : cornerDecoratedImageMap.values()) {
                                        for (Image image : decoratedMap.values()) {
                                                image.dispose();
                                        }
                                        decoratedMap.clear();
                                }
                                cornerDecoratedImageMap.clear();
                        }
                }
        }
        ////////////////////////////////////////////////////////////////////////////
        //
        // Font
        //
        ////////////////////////////////////////////////////////////////////////////
        /**
         * Maps font names to fonts.
         */
        private static Map<String, Font> m_fontMap = new HashMap<String, Font>();
        /**
         * Maps fonts to their bold versions.
         */
        private static Map<Font, Font> m_fontToBoldFontMap = new HashMap<Font, Font>();
        /**
         * Returns a {@link Font} based on its name, height and style.
         * 
         * @param name
         *            the name of the font
         * @param height
         *            the height of the font
         * @param style
         *            the style of the font
         * @return {@link Font} The font matching the name, height and style
         */
        public static Font getFont(String name, int height, int style) {
                return getFont(name, height, style, false, false);
        }
        /**
         * Returns a {@link Font} based on its name, height and style. Windows-specific strikeout and underline
         * flags are also supported.
         * 
         * @param name
         *            the name of the font
         * @param size
         *            the size of the font
         * @param style
         *            the style of the font
         * @param strikeout
         *            the strikeout flag (warning: Windows only)
         * @param underline
         *            the underline flag (warning: Windows only)
         * @return {@link Font} The font matching the name, height, style, strikeout and underline
         */
        public static Font getFont(String name, int size, int style, boolean strikeout, boolean underline) {
                String fontName = name + '|' + size + '|' + style + '|' + strikeout + '|' + underline;
                Font font = m_fontMap.get(fontName);
                if (font == null) {
                        FontData fontData = new FontData(name, size, style);
                        if (strikeout || underline) {
                                try {
                                        Class<?> logFontClass = Class.forName("org.eclipse.swt.internal.win32.LOGFONT"); //$NON-NLS-1$
                                        Object logFont = FontData.class.getField("data").get(fontData); //$NON-NLS-1$
                                        if (logFont != null && logFontClass != null) {
                                                if (strikeout) {
                                                        logFontClass.getField("lfStrikeOut").set(logFont, Byte.valueOf((byte) 1)); //$NON-NLS-1$
                                                }
                                                if (underline) {
                                                        logFontClass.getField("lfUnderline").set(logFont, Byte.valueOf((byte) 1)); //$NON-NLS-1$
                                                }
                                        }
                                } catch (Throwable e) {
                                        System.err.println("Unable to set underline or strikeout" + " (probably on a non-Windows platform). " + e); //$NON-NLS-1$ //$NON-NLS-2$
                                }
                        }
                        font = new Font(Display.getCurrent(), fontData);
                        m_fontMap.put(fontName, font);
                }
                return font;
        }
        /**
         * Returns a bold version of the given {@link Font}.
         * 
         * @param baseFont
         *            the {@link Font} for which a bold version is desired
         * @return the bold version of the given {@link Font}
         */
        public static Font getBoldFont(Font baseFont) {
                Font font = m_fontToBoldFontMap.get(baseFont);
                if (font == null) {
                        FontData fontDatas[] = baseFont.getFontData();
                        FontData data = fontDatas[0];
                        font = new Font(Display.getCurrent(), data.getName(), data.getHeight(), SWT.BOLD);
                        m_fontToBoldFontMap.put(baseFont, font);
                }
                return font;
        }
        /**
         * Dispose all of the cached {@link Font}'s.
         */
        public static void disposeFonts() {
                // clear fonts
                for (Font font : m_fontMap.values()) {
                        font.dispose();
                }
                m_fontMap.clear();
                // clear bold fonts
                for (Font font : m_fontToBoldFontMap.values()) {
                        font.dispose();
                }
                m_fontToBoldFontMap.clear();
        }
        ////////////////////////////////////////////////////////////////////////////
        //
        // Cursor
        //
        ////////////////////////////////////////////////////////////////////////////
        /**
         * Maps IDs to cursors.
         */
        private static Map<Integer, Cursor> m_idToCursorMap = new HashMap<Integer, Cursor>();
        /**
         * Returns the system cursor matching the specific ID.
         * 
         * @param id
         *            int The ID value for the cursor
         * @return Cursor The system cursor matching the specific ID
         */
        public static Cursor getCursor(int id) {
                Integer key = Integer.valueOf(id);
                Cursor cursor = m_idToCursorMap.get(key);
                if (cursor == null) {
                        cursor = new Cursor(Display.getDefault(), id);
                        m_idToCursorMap.put(key, cursor);
                }
                return cursor;
        }
        /**
         * Dispose all of the cached cursors.
         */
        public static void disposeCursors() {
                for (Cursor cursor : m_idToCursorMap.values()) {
                        cursor.dispose();
                }
                m_idToCursorMap.clear();
        }
        ////////////////////////////////////////////////////////////////////////////
        //
        // General
        //
        ////////////////////////////////////////////////////////////////////////////
        /**
         * Dispose of cached objects and their underlying OS resources. This should only be called when the cached
         * objects are no longer needed (e.g. on application shutdown).
         */
        public static void dispose() {
                disposeColors();
                disposeImages();
                disposeFonts();
                disposeCursors();
        }
}